Fix Python streaming examples in docs

[sztoplover-bit]

Summary

• fix the Python streaming examples in the root README and Python README
• update the quickstart and python local demo docs to pass stream_response=True
• show streamed output by iterating over response.output as AgentStreamResponse chunks

Why this is a local SDK/docs issue

The current Python examples show streaming usage that does not match the local AgentSquad.route_request() implementation in python/src/agent_squad/orchestrator.py. In the Python SDK, streamed chunk iteration happens when stream_response=True is passed and response.output is consumed as an async stream.

Validation

• verified the route_request(..., stream_response=False) signature and streaming branch in python/src/agent_squad/orchestrator.py
• verified the updated examples now match that behavior

Fixes #220